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Reason is the mental ability to deduce facts about the world, or to make valid inferences from prior knowledge. Humans do this with ease on a daily basis (other animals can't do it at all). For example, when we calculate a waiter's tip, or figure out why the car is making that funny noise, or estimate the angle to hit a cue ball, or even predict the existence of the '

,' we're using reason. Reason is the basis for virtually all our inferences and conclusions. Every theory then, scientific or otherwise, not only utilizes reason, but assumes it is trustworthy. If a particular theory were to somehow cast doubt on the validity of reason, if it were to make us think our inferences are dubious or invalid, then that theory would refute itself, since one needs reason to believe the theory in the first place. It turns out

is true, and he answered, "Because that belief will help me to survive and make it more likely that I'll have offspring." Apart from thinking him a bit crazy, you'd probably agree that his belief in heliocentrism is unjustified - that is, his reasons for holding the belief are invalid and irrational. As silly as it may seem, this little thought experiment helps us to understand why materialism cannot ultimately explain reason.

If materialism is true, then reason, like every other biological trait of humans, is merely a byproduct of blind natural selection; that is, it exists only because it happened to produce behavior that helped our ancestors survive and reproduce, not because it leads one to true beliefs. In other words, according to materialism, survival and sex are the ultimate "reasons" behind reason. Here's why that's a problem:

As our thought experiment above illustrates, beliefs that are merely byproducts of a non-rational process, or a biological impulse, are invalid and unjustified. We all know this intuitively. For instance, when people say things like, "You only think this is the best meal you've ever had because you're so hungry," or "He only thinks she's talented because he's attracted to her," or "You only believe in God because evolution has hardwired you to," they are rejecting a particular belief because they suspect it is based on non-rational impulses/processes - hunger, sexual attraction, natural selection - instead of reason. But, if materialism is true, then

. Like everything else, it evolved through the process of natural selection - a process that did not have truth in mind, only survival and reproduction.[1] That would mean that

every

belief we've arrived at through reason, and every theory, is invalid and unjustified. Hence, materialism, if true, calls into question the validity of reasoning, and with it all theories and beliefs based on reason. But one needs reason to believe materialism in the first place. Therefore, materialism is self-refuting, and irrational.

Atheist philosopher of NYU, Thomas Nagel, has written about the self-defeating nature of materialism recently in his book

Mind and Cosmos

(pictured below):

I agree with Alvin Plantinga that, unlike divine benevolence, the application of evolutionary theory to the understanding of our own cognitive capacities should undermine...our confidence in them... Evolutionary naturalism implies that we shouldn't take any of our convictions seriously, including the scientific world picture on which evolutionary naturalism itself depends.[2]

If this argument is correct, then materialism entails a type of rational inconsistency, or logical contradiction. Hence, it must be false. That means there is more to reality than just the physical. And whatever the non-physical part of reality is, it is compatible with reason. I believe theism provides a framework that fits this picture quite nicely. God is a rational entity who ordered the world (included us) in a rational way. Thus, if God exists, we would expect human reasoning to be valid. The human capacity for rationality, therefore, not only shows that materialism is false, it is also an additional reason to believe in God.

Not so obvious. Evolution can't "see" what an organism's belief is; evolution only selects

behavior

that helps organisms survive and reproduce. But we can easily think of false beliefs that would produce behavior that's helpful for survival. For instance, the belief, "All animals bigger than me want to eat me," might help me survive. Based on that belief, I would likely avoid many predators. But the belief is obviously false; cows don't want to eat me. Moreover, reason provides us with abilities that have nothing to do with our survival, such as being able to calculate the circumference of the Earth, or triangulate the distance of stars, or predict the next solar eclipse, or write an opera, or build a cathedral. None of those abilities are necessary for survival or reproduction, hence they're unlikely to be produced through blind natural selection.

2. Computers reason - they make rational inferences all the time; yet they are purely material objects. Thus, materialism does not destroy the trustworthiness of reason.

Philosopher William Hasker said it better than I could:

Computers function as they do because they have been constructed by human beings endowed with rational insight. A computer, in other words, is merely an extension of the rationality of its designers and users, it is no more an independent source of rational insight than a television set is an independent source of news and entertainment.[3]

I would add that computers have no understanding of the computations they make, but humans do. Hence, the "reasoning" computers exhibit falls short of true rationality, in my opinion. Moreover, human reasoning is different from computer reasoning in another important way - as I'll explain in my

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1. This criticism only applies to materialistic evolution. Theistic evolution would be exempt from the criticism because natural selection in that case would not be blind; rather, it would be sovereignly guided by God for a rational purpose.

2. Thomas Nagel,

Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False